I suppose it was inevitable after 45 years of intensive but mostly futile investigating the FBI this week said it pulled the plug on the Dan “DB” Cooper hijacking/ransom case.

You may recall that in November 1971, between Seattle and Reno, Cooper parachuted out of the back of an airliner he'd hijacked with a bag filled with $200,000 in stolen cash. He's never been found, though some of the stolen money was recovered.

According to the FBI, the agency learned of the crime in-flight and opened an extensive investigation that lasted 45. Calling it NORJAK, for Northwest hijacking, the FBI interviewed hundreds of people, tracked leads across the nation, and scoured the aircraft for evidence. By the five-year anniversary of the hijacking, the agency had considered more than 800 suspects and eliminated all but two dozen from consideration. Over years the case has mostly grown cold.

FBI

Artist sketches of D.B. Cooper, who vanished in 1971 with $200,000 in stolen cash

In 2008, looking to stir up something, the FBI said: "Who was Cooper? Did he survive the jump? And what happened to the loot, only a small part of which has ever surfaced? It's a mystery, frankly. We've run down thousands of leads and considered all sorts of scenarios. And amateur sleuths have put forward plenty of their own theories. Would we still like to get our man? Absolutely. "

But this week the FBI said it was closing the case to focus whatever efforts it had ongoing onto other more important cases.

“The mystery surrounding the hijacking of a Northwest Orient Airlines flight in November 1971 by a still-unknown individual resulted in significant international attention and a decades-long manhunt. Although the FBI appreciated the immense number of tips provided by members of the public, none to date have resulted in a definitive identification of the hijacker. The tips have conveyed plausible theories, descriptive information about individuals potentially matching the hijacker, and anecdotes—to include accounts of sudden, unexplained wealth. In order to solve a case, the FBI must prove culpability beyond a reasonable doubt, and, unfortunately, none of the well-meaning tips or applications of new investigative technology have yielded the necessary proof. Every time the FBI assesses additional tips for the NORJAK case, investigative resources and manpower are diverted from programs that more urgently need attention,” the FBI stated.